Zeolite based catalysts are generally known for catalytic hydrocarbon conversion operations, such as cracking. The cracking process involves breakdown of hydrocarbon vapours on contacting with cracking catalyst at a relatively high temperature. In this process, the catalyst becomes contaminated with carbon and high-boiling hydrocarbon. In order to remove the contaminants, the catalyst is subjected to regeneration before it is returned to the cracking zone. The catalyst is firstly purged with steam to remove hydrocarbon vapors and then is regenerated by burning of coke in regeneration zone. The regeneration temperature is many degrees higher than the reaction temperature. Generally, during the process of regeneration, the zeolite component of the catalysts loses a substantial portion of its crystallinity and activity. The zeolite catalysts referred to above are unstable when subjected to high temperatures, particularly in the presence of steam. Their catalytic activity is reduced rapidly. There had been a lot research done in this field of improving the stability of the catalyst. There are many literature in the prior art which teaches the attrition resistant zeolite based catalysts but there has been a very less information or knowledge of aluminium phosphate binder based zeolite catalyst which are stable and selective towards a particular category of hydrocarbons such as light olefins, LPG.
Following patents illustrate prior art processes and compositions which are different from present invention with respect to composition, process and performance.
U.S. Pat. No. 3,847,793 describes a process for conversion of hydrocarbons with a dual cracking component catalyst comprising ZSM-5 zeolite based catalyst and large pore zeolite based catalyst.
U.S. Pat. No. 6,137,022 discloses a process of making an olefin product from an oxygenated feedstock by contacting the feedstock in a reaction zone containing 15 volume percent or less of a catalyst, preferably a catalyst comprising a silica-alumina-phosphate molecular sieve.
U.S. Pat. No. 6,258,257 refers to a process for producing polypropylene from C3 olefins by a two-stage fluid catalytic cracking process having two types of catalysts made from zeolites of large pore and medium pore.
EP 0167325A3 relates to higher make-up of catalyst that may contain 2 or 3 times the amount of ZSM-5 sought for the equilibrium catalyst.
U.S. Pat. No. 4,309,280 describes a process for maximizing of LPG by adding very small amounts of powdered, neat ZSM-5 catalyst, characterized by a particle size below 5 microns to the FCC catalyst inventory.
U.S. Pat. No. 5,190,902, CA2156607A1 and CP 0643621B1 refer to a processes for the preparation of attrition resistant binder particles by spray drying of clay phosphate slurry which was initially taken to extreme pH conditions, adding zeolite and adjusting pH, spray drying followed by calcination.
U.S. Pat. No. 5,286,369 relates to an aluminum phosphate binder for binding various zeolites, prepared by reacting aluminum nitrate with phosphoric acid. The nitric acid which is a by-product as shown in equation below is detrimental to the activity of the zeolite, which is the main key component of the catalyst product. The presence of nitric acid in the precursor slurry will takeout framework aluminum present in the zeolite, which is responsible for creating bronsted acid sites required for cracking of hydrocarbon molecules.Al(NO3)3+H3PO4→AlPO4+3HNO3 
It may be noted that, higher the concentration of aluminum phosphate binder proportionally higher the content of nitric acid and to similar extent be the detrimental effect on zeolite activity.
U.S. Pat. No. 4,784,745 relates to a catalyst and a process for enhancing gasoline octane number of gasoline, wherein said shape-selective zeolite is selected from the group having the structure of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-34, ZSM-35, ZSM-38, ZSM-48, ZSM-50, TMA Offretite and Erionite.
U.S. Pat. No. 4,828,679 relates to octane and total yield improvement in catalytic cracking of petroleum fractions under cracking conditions by adding to conventional cracking catalysts small amounts of an additive catalyst comprising a class of zeolites characterized by a silica to alumina mole ratio greater than 12 and a constraint index of 1 to 12 wherein the zeolite additive catalyst has a crystal size of between 0.2 to 10 microns.
U.S. Pat. No. 4,867,863 deals with a Resid catalytic cracking process utilizing ZSM-5 for increased gasoline octane.
U.S. Pat. No. 5,039,640 refers to a catalyst composition comprising of large pore crystalline molecular sieve component and an MCM-22 zeolite for catalytic cracking of a hydrocarbon oil to provide a product of increased octane number and increased C5+ gasoline content.
U.S. Pat. No. 5,055,437 deals with multi-component catalyst mixture having Ga in ZSM-5 and process for catalytic cracking of heavy hydrocarbon feed to lighter products.
U.S. Pat. No. 5,348,643, relates to a process for converting feedstock hydrocarbon compounds over a catalyst composition comprising clay and a zeolite component, at least one of which has been treated with a phosphorus-containing compound, which is spray dried at a low pH, to produce high octane gasoline and increased lower olefins, especially propylene and butylenes.
U.S. Pat. No. 5,846,402 relates to a process for selective catalytic cracking of a petroleum-based feedstock to produce a product having a high yield of liquefied petroleum gas (LPG) and light olefins having 3 to 4 carbons.
U.S. Pat. No. 5,997,728, refers to a process for cracking of heavy feed in an FCC unit, to enhance light olefins, without excessive production of aromatics, or loss of gasoline yield with large amounts of shape selective cracking additive preferably at least 10 wt % additive, of 12-40% ZSM-5 on an amorphous support, equivalent to more than 3.0 wt % ZSM-5 crystal circulating with equilibrium catalyst.
U.S. Pat. No. 6,613,710 deals with a process for preparing bi-functional catalyst comprising of molecular sieves, modified clay and semi-basic alumina for effective cracking of high boiling petroleum feedstock to provide simultaneously, enhanced yields of Liquefied Petroleum Gas (LPG) and reduction of undesirable bottoms.
U.S. Pat. No. 6,677,263, discloses a catalytic promoter comprising of 5-65 wt % of modified HZSM-5 zeolite with Zn, P, Ga, Al, Ni and rare earth elements in an amount 0.01-10.37 wt % based on total weight of HZSM-5 zeolite to increase gasoline octane number and an increased lower olefin yield.
The U.S. Pat. No. 7,517,827 teaches preparation of cracking catalyst composition having high selectivity towards production light olefins such as LPG, propylene etc. achieved through treating the zeolite with sodium free basic compound with or without phosphate.